[CI] Add clang job and setup concurrency

[christophfroehlich]

• This adds a semi-binary job using clang. I fixed all what clang was complaining about.
• use humble branch of realtime_tools for humble CI

Additionally, I added the concurrency settings which now automatically cancel running workflows if anything is pushed to PRs.
https://docs.github.com/en/actions/writing-workflows/choosing-what-your-workflow-does/control-the-concurrency-of-workflows-and-jobs

[codecov]

Codecov Report

Attention: Patch coverage is 97.91667% with 1 line in your changes missing coverage. Please review.

Project coverage is 83.59%. Comparing base (de42962) to head (7fad712).
Report is 2 commits behind head on master.

Files with missing lines	Patch %	Lines
...ntroller/test/test_trajectory_controller_utils.hpp	66.66%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1407      +/-   ##
==========================================
- Coverage   83.60%   83.59%   -0.01%     
==========================================
  Files         122      122              
  Lines       11007    11018      +11     
  Branches      934      935       +1     
==========================================
+ Hits         9202     9211       +9     
- Misses       1494     1495       +1     
- Partials      311      312       +1     

Flag	Coverage Δ
unittests	83.59% <97.91%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
.../include/admittance_controller/admittance_rule.hpp	100.00% <100.00%> (ø)
...ude/admittance_controller/admittance_rule_impl.hpp	92.82% <100.00%> (+0.16%)	⬆️
...dmittance_controller/src/admittance_controller.cpp	74.15% <100.00%> (ø)
...iff_drive_controller/src/diff_drive_controller.cpp	76.51% <100.00%> (ø)
...ller/test/test_load_forward_command_controller.cpp	100.00% <100.00%> (ø)
..._broadcaster/test/test_joint_state_broadcaster.cpp	96.62% <100.00%> (ø)
...include/joint_trajectory_controller/tolerances.hpp	79.79% <100.00%> (ø)
...include/joint_trajectory_controller/trajectory.hpp	75.00% <100.00%> (ø)
...ory_controller/src/joint_trajectory_controller.cpp	83.90% <100.00%> (ø)
joint_trajectory_controller/src/trajectory.cpp	91.35% <100.00%> (ø)
... and 5 more

... and 5 files with indirect coverage changes

[saikishor]

LGTM in general. Some castings are new to me hahaa
If the CI is happy, I'm fine with it

[christophfroehlich]

LGTM in general. Some castings are new to me hahaa If the CI is happy, I'm fine with it

I used now explicit iterator's difference_type cast instead of the ptrdiff(which is normally the same..)